Gateway advertisement in a wireless mesh

ABSTRACT

A computing environment containing a mesh network that is adapted to provide a reliable transport mechanism over which services may be delivered. Nodes of the mesh can automatically select routable addresses without conflicts, which allows nodes of the mesh to be accessed, even as the mesh changes through the addition or deletion of nodes Also, nodes communicate with a protocol that supports service advertisements These advertisements can identify mesh nodes that supply services, such as file or print servers, for which devices that have not yet connected to the network may be searching Advertisements can also identify services to be used by nodes in the network, allowing, for example, a node to select a gateway providing a reliable connection to an external network. The mesh network can be used as a transport for communication using protocols, such as TCP/IP, that generally exhibit poor performance when using unreliable transports.

RELATED APPLICATION(S)

This Application is a Continuation of and claims benefit from U.S.patent application Ser. No. 14/641,808 that was filed on Mar. 9, 2015,and that is a Continuation of U.S. patent application Ser. No.12/392,728 (U.S. Pat. No. 8,976,795), filed Feb. 25, 2009 (issued Mar.10, 2015), each of which is incorporated herein by reference in itsentirety.

BACKGROUND

Devices connected to computer networks have a need for a unique networkaddress in order to communicate on the network In many networks, thenetwork address is allocated or assigned automatically, avoiding theneed for manual configuration by a user. The automatic allocation ofaddresses is typically centralized in a dedicated device on the networkthat provides an address-assignment service, such as the Dynamic HostConfiguration Protocol (DHCP). The use of a centralizedaddress-assignment service avoids the occurrence of network addressconflicts.

Various types of computer networks exist. A traditional computer networkincludes network infrastructure, such as routers and switches, as wellas dedicated devices providing network services such as DHCP.

A mesh network is a self-learning network of loosely connected computingdevices. The devices connected to the mesh typically distribute packetsthroughout the mesh, allowing for the network to operate with limited orno infrastructure. The mesh network requires no maintenance, and can bevery robust if a sufficient density of connected computing devices hasbeen achieved. Mesh networks are particularly useful in developingcountries lacking the infrastructure to form a traditional computernetwork.

Some computing devices may offer a service to other devices, such as aDHCP service, a data storage service, or a printing service. It is oftendesirable for such a device to advertise to other devices the service(s)it provides. For example, a router in a network may advertise itsrouting capability to other devices using a protocol such as theInternet Control Message Protocol (ICMP). An ad-hoc device, such as adevice operating over the Bluetooth® protocol may also advertise aservice it provides. For example, a cellular phone capable of exchangingdata over a cellular network may advertise that capability over aBluetooth® protocol to other devices. A Bluetooth® equipped laptopcomputer, for example, could then connect to external networks throughthe cellular phone to exchange data with other computers.

SUMMARY

A mesh network is adapted to act as a reliable transport, despite thevarying and ad hoc nature of a mesh network. For example, the mesh maybe adapted to serve as a transport mechanism for communications usingTCP/IP or other higher level protocols or may allow devices to useservices provided by mesh nodes, even when out of range of wirelesscommunication range with those mesh nodes.

In one aspect, the mesh can be used as an access network to othernetworks. A node in the mesh that can serve as a bridge to anothernetwork advertises over the mesh that it is capable of acting as agateway. Other nodes in the network can receive such advertisements, anduse them to select a gateway for communication outside the mesh.

The advertisements may provide information that allows each node in themesh to select a desirable gateway node as its default gateway. Part ofthis information may be contained with the advertisements themselves.Though, another part of this information may be obtained from the timingwith which advertisements are received.

Information in the advertisement may identify characteristics of thepath between the gateway and the node receiving the advertisement. Forexample, the advertisement may indicate a number of hops in the path.Such information may be incorporated into an advertisement by theoperation of nodes in the mesh network as the advertisement propagatesthrough the mesh network. For example, the advertisement may begenerated by a gateway node with a null value in a hop count field. Aseach node receives an advertisement, it may increment the hop countfield and then forward the advertisement to other nodes in the meshnetwork.

Timing related to receipt of advertisements may also be used inselecting a default gateway. Each gateway may generate advertisementsrepeatedly at intervals that will allow a node to identify whether thepath through the mesh network to the gateway has been lost or, as aresult of mesh reconfiguration, changed. Each node may repeatedly updateits selection of a default gateway, selecting as a default a gatewaythat is reachable over an efficient path. The gateway selection maychange at the transport level faster than a change in the defaultgateway that might otherwise occur as a result of a communicationsfailure at a higher protocol layer when a default gateway becomesunavailable. As a result, the mesh network provides a reliable transportfor any communications through the selected gateway.

The foregoing is a non-limiting summary of the invention, which isdefined by the attached claims.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a diagram of a computing environment in which the inventionmay be practiced;

FIG. 2 is a block diagram of components to implement a gateway nodeaccording to some embodiments of the invention;

FIG. 3A is a diagram of a computing environment in which a mesh node mayselect a default gateway;

FIG. 3B is a diagram of a routing table for gateway nodes for a meshnode illustrated in the computing environment of FIG. 3A;

FIG. 4 is a flowchart of a method of selecting a default gateway nodefor a mesh node, according to some embodiments of the invention;

FIG. 5 is a flowchart of a method of distributing service advertisementsthroughout the mesh network, as well as to computing devices outside themesh network;

FIG. 5A is a method of advertising services to computing devices outsidethe mesh network;

FIG. 5B is an alternate method of advertising services to computingdevices outside the mesh network; and

FIG. 6 is a method for a mesh node to automatically assign a uniquenetwork address to itself, including resolving any conflicts to mayarise with other mesh nodes on the mesh network.

DETAILED DESCRIPTION

The inventors have recognized and appreciated modifications ofconventional mesh networks that can enable the network to be used tosupport services in scenarios where the ad hoc and unreliablecharacteristics of those networks would otherwise not be acceptable. Inthis way, the relative flexibility and ease of creation of mesh networkscan be leveraged to deliver services in a wide range of locations, evenwhere network infrastructure has not yet been deployed or isunaffordable or otherwise unavailable.

One adaptation that may be incorporated into a mesh network is the selfassignment of addresses for nodes on the network so that each node canbe uniquely identified, either by other nodes on the network or devicesoutside the network that may wish to obtain services that requirecommunication with nodes on the mesh. Such self-assignment may beperformed in a way that avoids conflicts, even as the network grows,splits or reconfigures as nodes join and leave the mesh network.

A further adaptation that may be incorporated into a mesh network is theadvertisement of services to devices outside the network. Nodes of themesh may advertise to other nodes on the mesh the services they provide.Nodes that can act as an access point to the mesh network may collectand aggregate such advertisements. The aggregated advertisements,identifying services available through the mesh, may be distributed tocomputing devices that have not yet joined the mesh network. Otherdevices outside the mesh network may use the aggregated advertisementsto locate services, and the services may be used as criteria for joiningthe mesh network.

Further, a mesh network may be adapted to support reliable connectionsthrough the mesh to gateways for another network. These connections maybe formed by allowing each node to select as a default a gateway thatcan be reliably reached from that node. The selection may be changedwith a frequency that helps ensure that there will be a reliable gatewayselected for communication even if changes in the mesh network disruptcommunication with some gateways.

Selection of a default gateway may be enabled by configuring gatewaynodes to repeatedly advertise their presence. Information associatedwith the advertisements may then be used to enable other nodes to keeptheir selection of a gateway node current.

These adaptations may be used separately or in any combination tofacilitate use of the mesh network in ways that mesh networks are notnormally used. For example, the mesh network may be used as a transportfor higher level network protocols. As a specific example, TCP/IPcommunications generally perform poorly over unreliable transports.Communications using TCP/IP and other protocols that require deliveryconfirmation experience delays when a message is not delivered as aresult of a node in a communication path being unavailable. One cause ofdelay is that, when the message does not reach its intended destination,no message acknowledgement is received. In this case, the sending devicewaits until a time out period expires and may attempt severalretransmissions until the sending device determines that communicationover the initially selected path has failed and reconfigures itself touse a different path. By selecting as a default a gateway, or other nodethat provides a service, based on the reliability and the availabilityof a connection to that node, and by updating the selection morefrequently than the time it would otherwise take to identify failurealong a path, reliable communication can be maintained.

Alternatively or additionally, a mesh network according to someembodiments may expand the physical radius around a file server or printserver from which other computing devices can access such services.

These and other functions may be implemented using a mesh network thathas been adapted for reliable communication.

FIG. 1 illustrates a computing environment in which the invention may bepracticed. The computing environment of FIG. 1 includes a mesh network101, which includes a plurality of mesh nodes, such as mesh nodes 103,105, 107 and 109. While the mesh nodes 103, 105, 107 and 109 areillustrated in FIG. 1 as the same type of computing device, they may beany suitable computing device, such as laptop computer, desktopcomputer, PDA, mobile device, or smart phone, capable of communicatingover a computer network. The mesh nodes may be loaded with software,written in any suitable language, including as an operating system, suchas variants of the WINDOWS® operating system developed by MicrosoftCorporation. The mesh nodes may be configured through any suitablecombination of software or hardware to exchange and forward networkpackets with one another through the mesh network over any suitablecomputer communications medium, including wired communication orwireless communication, as the invention is not limited, in thisrespect. In the embodiments of the invention described below, the meshnetworks communicate over a wireless medium, such as the 802.11s variantof the wireless Ethernet protocol. However, any suitable protocol may beused for communication between mesh nodes.

The mesh network may include one or more specially configured meshnodes, called gateway nodes or mesh portal points, that are connected toone or more computer networks outside the mesh network. A gateway nodebridges the mesh network with an external network, allowing other meshnodes to communicate with devices outside the mesh. The external networkcould be an infrastructure network, such as the Internet, but theexternal network could also have other forms. When a user of a mesh nodethat is not a gateway node has a need to communicate with a deviceoutside the mesh, the mesh node can direct a network packet to anappropriate gateway node that forwards the network packet to thecomputing device outside the mesh. Packets sent from a computing deviceoutside the mesh that are destined for a mesh node are directed to thegateway node, which may then forward the packets to the appropriate meshnode. The forwarding functionality of the gateway node may be done inany suitable way, including by using network address translation (NAT),as is known in the art.

Three of the mesh nodes in the mesh network 101 in the example of FIG. 1are configured as gateway nodes, gateway nodes 103, 107 and 109.However, other mesh networks in which the invention may be practiced mayinclude a greater or lesser number of gateway nodes. By means of gatewaynodes, a mesh network may be connected to multiple external networks,and multiple gateway nodes may be configured to access the same externalnetwork. In the example of FIG. 1, the mesh network 101 is connected totwo separate external networks, private external network 111, and theInternet 113. A single gateway node 107 is illustrated as connected tothe private external network 111, while two gateway nodes, gateway nodes103 and 109, are illustrated as connected to Internet 113. Theconnection between a gateway node and an external network may be made inany suitable way, over any suitable communications medium, includingwired and wireless communication, in the example illustrated in FIG. 1,gateway nodes 109 and 107 are connected to Internet 113 and privateexternal network 111, respectively, through a wired communicationsmedium, and gateway node 103 is connected to the Internet 113 over awireless communications medium through an access point 115.

A mesh network typically has a more transient nature than a traditionalnetwork. For example, mesh nodes, including gateway nodes, may suddenlyno longer be connected to the mesh network. In some environments inwhich the invention may be practiced, a mesh node may not provide anyindication to other mesh nodes in the mesh network that it has left orhas disconnected from the mesh network. A mesh node may leave thenetwork for any number of reasons, both voluntary and involuntary. Forexample, a mesh node may suffer a hardware or software failure, or itmay have been intentionally powered down by a user in order to transportthe device configured as a mesh node to another location.

In addition, as mesh nodes leave the mesh network, it is possible for amesh network to split into two or more disjoint mesh networks, in whichthe new resulting mesh networks may not include all the gateway nodesthat belonged to the single mesh network. A mesh network may also joinwith another mesh network, which could result in an additional number ofgateway nodes that could be available to a mesh network.

Accordingly, mesh nodes that rely on a gateway node for connectivity todevices on an external network may need a way to detect the presence orabsence of gateway nodes in the mesh network. In some embodiments of theinvention, each gateway node on a mesh network generates anadvertisement, and may periodically transmit the advertisement to othermesh nodes, thereby alerting other mesh nodes of its continued presence.The advertisement may be transmitted according to any suitable protocol,such as ICMP. A mesh node may then track the gateways from which it hasrecently received an advertisement in order to take account of thegateways currently available on a mesh network.

If a mesh node has received an advertisement from more than one gateway,in some embodiments of the invention, the mesh node may select a singlegateway as a default gateway. The default gateway may be the firstgateway to which the mesh node forwards packets destined for a computingdevice on an external network. For example, a user of a mesh node, suchas mesh node 105, may have a need to communicate with a computer outsidethe mesh over the Internet 113. Mesh node 105 may then be configured todirect a TCP/IP packet encapsulated for transmission over the meshnetwork to a particular gateway node connected to the Internet 113.While the mesh network 101 includes two gateway nodes connected to theInternet 113, the mesh node 105 may be configured to select only one ofthem, such as gateway node 109, as the default gateway node to which themesh node 105 first directs packets destined to computers over theInternet. The selection of the default gateway node may be made in anysuitable way. In some embodiments of the invention, the mesh node mayselect the default gateway node by taking into account characteristicsof a network path between the mesh node and each gateway node.

Mesh nodes may provide additional services besides the connectivity toan external network that is provided by any gateway node. A mesh nodeproviding a service may make the service available to other nodes in themesh network. In the example illustrated by FIG. 1, mesh node 107 isconnected to storage data 117, and provides data storage services to themesh network, and mesh node 105 is connected to printer 119, andprovides printing services to the mesh network. However, any suitableservice may be provided by a mesh node, as the invention is not limitedin this respect.

Due to the transient nature of many mesh networks, the servicesavailable in a mesh network can change over time. Thus, as with theavailability of gateway nodes, it would be useful for a mesh node tohave an accurate account of any services currently available to it onthe mesh network. Accordingly, a mesh node, such as mesh nodes 105 and107, that provides a service to other mesh nodes, may advertise theavailability of that service to other nodes in the mesh network. Anadvertisement sent by a mesh node providing a service to other nodes inthe mesh may be made over any suitable protocol. In some embodiments ofthe invention, the advertisements are sent using protocols at networkinglayer three or above, such as a Universal Plug and Play (UPnP™)Discovery Protocol or a Web Services Discovery (WSD) Protocol. Based onthe advertisements it has recently received from other mesh nodesproviding services, a mesh node may keep track of the services currentlyavailable on the mesh network.

Devices outside the mesh network may also have a need for certainservices provided by the mesh network For example, the computingenvironment illustrated by FIG. 1 also includes a computing device 121that is outside the mesh network, but that may be within a geographicaldistance that includes the range of the mesh network 101. A user of thecomputing device 121 may have a need to print a document, but have noaccess to a printer. Accordingly, continuing in the current example, itwould be useful for the computing device 121 to be able to have accessto the printing service provided by the mesh node 105. However, becausethe computing device 121 is not part of the mesh network, it does notreceive the service advertisements distributed by mesh node 105, andtherefore has no knowledge of the availability of the printing serviceprovided by the mesh network.

It may also be useful for users of devices outside the mesh network tobe made aware of services provided by nodes in the mesh. In someembodiments of the invention, one or more of the mesh nodes mayaggregate the advertisements received from other mesh nodes providingservices, and convert the aggregated advertisements from the protocol inwhich they were received to a second protocol. In some embodiments ofthe invention, the second protocol may be a suitable protocol, such as alayer two networking protocol, in which a mesh node could communicatewith a device such as the computing device 121 outside the mesh. Theaggregated and converted advertisements may then be transmittedaccording to the second protocol to computing devices not in the meshnetwork. A user of a device outside the mesh network, such as thecomputing device 121, having been made aware of the services provided bythe mesh network, may then choose to have the computing device join themesh network in order to take advantage of any services provided by themesh.

One of the services that is typically provided in a traditional networkis the automatic assigning of a network address to a computing devicethat is unique on the network, which is often accomplished using theDHCP protocol. While it is also very useful for devices in a meshnetwork to be automatically assigned a unique network address, the useof the DHCP protocol is not well suited for a mesh network, because DHCPtypically requires a dedicated server.

Accordingly, in some embodiments of the invention, a mesh node in a meshnetwork may be configured to automatically assign a network address toitself. It may compute a network address for itself using any suitablemethod, and start using that network address to communicate with othermesh nodes. If the mesh node detects that another mesh node isconfigured to use the same network address, it may then resolve theconflict by computing a different network address, and using thatdifferent network address to communicate with other mesh nodes. When anetwork address assigned to the mesh node does not cause conflicts withany other mesh nodes, in some embodiments of the invention, the meshnode may store the non-conflicting network address in suitable computerstorage, such as a non-volatile memory. The mesh node may then re-usethe stored network address the next time it needs to determine a uniquenetwork address such as the next time the mesh node is powered on.

FIG. 2 illustrates a block diagram of components to implement a gatewaynode 200, such as one of gateway nodes 103, 107 and 109 in the exampleof FIG. 1, according to some embodiments of the invention. It should beunderstood that the number of components illustrated in FIG. 2 is not alimiting factor of the invention. The functionality ascribed to a singlecomponent illustrated in FIG. 2 could be implemented by multiplecomponents, while multiple components in FIG. 2 could be implemented asa single component in other embodiments of the invention. Additionally,while in the embodiment of FIG. 2, the illustrated components except forhardware 210 are implemented in software developed in any suitableprogramming language executed on a processor within gateway node 200,many of these components may also be implemented in hardware, or in anysuitable combination of hardware and software. In addition, many of thecomponents described as applying to gateway 200 may also apply to a meshnode that is not a gateway node, such as mesh node 105, although somedifferences will be noted below.

The gateway node 200, as illustrated in FIG. 2, may bridge a meshnetwork with an external network, allowing mesh nodes to connect throughit to the external network. In the embodiment of FIG. 2, the meshnetwork and the external network are illustrated as having separatenetwork adapters, external adapter 202 and mesh adapter 204. While, themesh adapter 204 may typically be a wireless network adapter, theinvention is not limited in this respect, and in general, either adaptermay be any suitable network adapter, supporting any suitable combinationof wired or wireless network communication.

The external adapter 202 and the mesh adapter 204 may be any combinationof hardware or software. They may be separate physical adapters, or onephysical adapter implemented as two separate logical adapters. Forexample, the gateway node 200 may be loaded with software, that whenexecuted on a processor, allows the same physical hardware to interleaveoperations for two or more network adapters, creating the appearance ofmore logical network adapters than may be apparent from the physicalhardware. In the embodiment illustrated in FIG. 2, both external adapter202 and mesh adapter 204 are two logical adapters exposed by an IMDriver 206, and are implemented using a single physical wireless networkadapter. This may be done in any suitable way. In the embodimentillustrated in FIG. 2, the IM driver 206 multiplexes and demultiplexesdata from both adapters and passes data to a miniport driver 208. Theminiport driver 208 may interface with hardware 210, which may includethe actual physical network adapter.

Network packets may be transmitted over external adapter 202 and meshadapter 214 through one or more network stacks implemented on thegateway node 200. The example illustrated by FIG. 2 includes two networkstacks, TCP/IP stack 212 for the external adapter 202, and TCP/IP stack214 for the mesh adapter 204. The gateway node 200 may also include abridge 216 for bridging the two networks, and for conveying networkpackets between a mesh node and a device on an external network. Thebridge 216 may include NAT services to perform address mapping foraddresses from the private interface (represented by the mesh adapter204) to the public interface (represented by the external adapter 202).The address mapping may be done in any suitable way. In some embodimentsof the invention, the mapping may only be kept alive for a certainperiod of time (e.g., 30 seconds) for UDP connections, while for TCPconnections, the mapping may be maintained for the life of theconnection. It is to be noted that a mesh node that is not a gatewaynode may only include one adapter, such as mesh adapter 204, and oneTCP/IP stack, such as TCP/IP stack 214. A mesh node that is not agateway node may also not include the bridge 216.

The gateway node 200 may also include mesh services 218, which mayimplement the management and configuration logic for the gateway node.The mesh services 218 may include an address and gateway manager (AGM)220, a mesh portal manager (MPM) 222, a topology manager (TM) 224, stateinformation 226, address logic 227, a DNS proxy 228, and a DNS cache230. Mesh services 218 may expose an API 232 to application(s) 234making use of mesh functionality and to a user interface 236, used forconfiguring and managing the mesh network.

The AGM 220 may implement the gateway advertisement protocol, generatingadvertisements, and periodically transmitting them to other mesh nodes.Mesh nodes may identify a node as a gateway node, such as gateway node200, based on the receipt of a gateway advertisement from that node, andmay accordingly select that gateway to direct packets to a computingdevice on an external network. The advertising functionality ascribed toAGM 220 may not be performed in a mesh node that is not a gateway node.

The AGM 220 may also generate and store state information 226 in asuitable format, such as a routing table, regarding gateway nodes forwhich it has received advertisements. The state information 226 may alsoinclude information about characteristics associated with the pathbetween the current node and each gateway node from which it hasreceived an advertisement.

The AGM 220 may also perform address configuration and duplicate addressdetection. In the case of a conflict between addresses on the meshnetwork and the external network, the AGM 220 may generate anotification, which could be used by the user interface 236 and addresslogic 227 to reconfigure the address.

In some embodiments of the invention, address logic 227 implements thefunctionality to generate and assign a unique network address for thecurrent node, including resolving an address conflict, should it occur.It may store a known non-conflicting network address in a suitablecomputer storage medium on the gateway node 220, which could be aportion of the state information 226.

The MPM 222 may determine if the current node may be configured as agateway node. This determination may be based at least in part onwhether the current node has connectivity on two interfaces, such asexternal adapter 202 and mesh adapter 204. In the embodiment of theinvention illustrated by FIG. 2, the MPM 222 may obtain connectivityinformation about the two interfaces from the IM driver 206. If itdetermines that the current node may be configured as a gateway node,such as is the case for gateway node 200 illustrated by FIG. 2, the MPM222 may configure the bridge 216. In some embodiments of the invention,prior to bridging the two network interfaces, the MPM 222 may verifythat the network address on the external network does not fall in thesame range as network addresses on the mesh network. In the unlikelyevent that there is a conflict, in some embodiments of the invention,the bridge is not established between the two interfaces. If a conflictis detected, the MPM 222 may provide an indication to the user of themesh node, such as through the user interface 236, that IT interventionmay be required. Alternatively, two or more address ranges could beimplemented for all devices in the mesh, in order to mitigate anyconflict that may arise.

The TM 224 may be used for diagnostic purposes, and may aid a user indetermining why a failure may be occurring on the mesh network. Forexample, it may provide the functionality to build a topology map of themesh network and provide that to a user via the user interface 236. Inconjunction with the TM driver 206, the TM 224 may also implement atrace route API that may collect information about mesh nodes ittraverses, as well as timing information to reach a given destination.

The gateway node 200 may also contain a Domain Name System (DNS) proxy228 that relays DNS requests sent by mesh nodes to a DNS server on theexternal network, and thus acts as a DNS resolver for the mesh nodes.For optimization, in some embodiments of the invention, the gateway modemay implement DNS information caching, such as via DNS cache 230. As isknown in the art, DNS cache 230 may store the results of recently issuedDNS requests in order to avoid having to issue the requests again to aDNS server on an external network. Thus, the DNS cache 230 cansignificantly improve the perception of connection speed on the mesh.DNS proxy and DNS cache 230 may be implemented in any suitable way,including using known techniques, and any suitable combination ofsoftware and computer storage media.

FIG. 3A illustrates a computing environment in which a mesh node mayselect a default gateway, according to some embodiments of theinvention. FIG. 3A includes a mesh network 302, and two externalnetworks, external network 304 and 306. The mesh network 302 includesthree gateway nodes, gateway nodes 308, 310 and 312. Gateway nodes 308and 310 are both connected to the external network 304, via accesspoints 314 and 316, respectively. Gateway node 306 is connected toexternal network 306 through access point 318. The mesh network 302 alsoincludes other mesh modes that are not gateway nodes, such as mesh nodes320, 322, 324, 326 and 328, that may communicate with devices outsidethe mesh on external network(s) 304 and/or 306 using one or more of thegateway nodes on the mesh.

According to some embodiments of the invention, each of gateway nodes308, 310 and 312 periodically broadcasts advertisements that aredistributed to other nodes through the mesh. A mesh node may keep trackof the gateway nodes from which it has received advertisements, such asby means of storing that information in a routing table in stateinformation 226, in the example illustrated by FIG. 2. A mesh node mayalso associate one or more characteristics, such as a metric, with apath between itself and each gateway node for which it has receivedadvertisements. The metric may be based on any suitable characteristics,such as the number of hops in the network path between itself and thegateway node, or the bandwidth, latency, or load associated with thenetwork path. While in some embodiments of the invention, the metric maybe calculated by the mesh node based on any suitable characteristics asdescribed above, in some embodiments of the invention, the metric mayalternatively or additionally be derived, at least in part, frominformation obtained from the gateway advertisement.

In some embodiments of the invention, when a mesh node receives anadvertisement originating from a gateway node, it may forward theadvertisement to other mesh nodes, with the addition of one or moreassociated characteristics. A mesh node may derive a metric by takinginto account the additional associated characteristics in theadvertisement. Any suitable additional characteristics may be includedin the forwarded advertisement, including the number of hops theadvertisement has traveled so far since it left the gateway node. Insome embodiments of the invention, the metric is also stored with thestate information, such as a routing table,

FIG. 3B illustrates a routing table 350 for the mesh node 320. Mesh node320 has received an advertisement from all three gateway nodes in themesh network, because all three gateway nodes are stored in its routingtable. Each gateway is referenced in the routing table by a uniqueidentifier, which may be any suitable identifier, such as the networkaddress on the mesh network of the gateway. In the example of FIG. 3B,gateway network addresses 352, 354 and 356 for gateway nodes 312, 310and 308, respectively, are stored in the routing table 350.

The routing table 350 also contains a metric for each of the threegateways based on characteristics of a path between the mesh node andthe gateway node. FIG. 3A illustrates three paths between the mesh node320 and three gateway nodes: a path 330, between the mesh node 320 andthe gateway node 308, a path 332 between the mesh node 320 and thegateway node 310, and a path 334 between the mesh node 320 and thegateway node 312. Accordingly, each of these paths is associated with ametric that is stored in the routing table 350. For example, metrics358, 360 and 362, associated with the paths to gateway nodes 312, 310and 308, respectively, are stored in the routing table, and associatedwith the gateway nodes. In the example of FIGS. 3A and 3B, based atleast in part on the metrics stored in the routing table 350, the meshnode 320 may select a default gateway node.

In some embodiments of the invention, more than one default gateway nodemay be selected. This may be appropriate, for example, if the meshnetwork has gateway nodes connected to two otherwise unconnectedexternal networks. Some mesh nodes, according to some embodiments of theinvention may also make use of multiple routing tables, for example,creating a separate routing table for each external network.

FIG. 4 is a flowchart of a method of selecting a default gateway nodefor a mesh node, such as mesh node 320 in FIG. 3A, according to someembodiments of the invention. It should be appreciated that while theembodiment of FIG. 4 describes the process in connection with selectinga gateway node, a similar process may be performed to select a defaultmesh node providing another type of service besides connectivity to anoutside network, such as a DNS service. The method may be implemented inany suitable way, and in any suitable combination of hardware orsoftware developed in any suitable programming language. In theembodiment of the invention illustrated by FIG. 2, a portion of themethod may be implemented in the address and gateway manager 220.

In the embodiment illustrated by FIG. 4, the method may start at block402, when a mesh node receives an advertisement originating from agateway node, also known as a mesh portal point (MPP). The mesh node maybe adapted to receive messages from other mesh nodes over a networkadapter connected to the mesh network, such as mesh adapter 204illustrated in FIG. 2. One or more of the messages received by the meshnode may be formatted to indicate that the message(s) corresponds to anadvertisement transmitted by a gateway node. In other embodiments,however, the method illustrated by FIG. 4 may be invoked periodically bythe mesh node, or may be invoked in response to other events besides thereceipt of an advertisement from an MPP.

If the method is invoked in response to receiving an advertisement froman MPP, the advertisement may be generated and transmitted by the MPPaccording to any suitable protocol. The protocol may be a knownprotocol, including ICMP, or it may be a special purpose protocoldeveloped for advertising gateway nodes in a mesh. Some embodiments ofthe invention may make modifications to a known protocol, such asthrough the use of option fields in a header of a message sent accordingto the known protocol.

Regardless of the type of protocol used, based on the receivedadvertisement, the mesh node may identify the node that generated themesh node as an MPP on the mesh network. In some embodiments of theinvention, an MPP may also include in the advertisement additionalinformation, such as a regular time period in which it broadcastsadvertisements, a DNS server, or specific routes to reach specificcomputing devices on an external network to which the MPP is connected.The additional information may be included in the advertisement in anysuitable way, including by making use of one or more option fields inthe protocol, as described above.

Regardless of any additional information contained within the receivedadvertisement, the mesh node then, at block 404, may check if the MPP isa new MPP. This may be done in any suitable way, including checking tosee if the MPP from which it just received an advertisement is presentin a routing table, such as routing table 350 illustrated in FIG. 3B. Ifthe mesh node determines that the MPP is new, the process may proceed toblock 406, in which the mesh node may add an entry for the MPP in therouting table. The entry in the routing table may take any suitableform, and may include an identifier, such as network address, for theMPP.

After the step at block 406 is performed, or if the mesh node haddetermined at block 404 that the MPP was not a new MPP, the MPP proceedsto block 408. At block 408, the mesh node may determine if it has notreceived an advertisement from any known MPP within an expected timeinterval. It may do this in any suitable way, including by checking allthe gateway nodes in its routing table. In some embodiments of theinvention, the expected time interval may be a value configured on themesh node itself as applying to any MPP in the mesh, while inembodiments of the invention in which an MPP includes a time period inthe advertisement, the value of the expected time interval may be basedon time period included in the advertisement, and therefore, might beparticular to that MPP. In embodiments in which the time period might beparticular to an MPP, the mesh node may track that time period in asuitable location, such as the routing table.

If the mesh node determines at block 408 that it has not received anadvertisement from any MPP(s) within an expected time period, this maybe an indication that the stale MPP(s) are no longer active, and mayhave either left the mesh network, or have become unreachable from themesh node. The mesh node may then proceed to block 410, in which it mayupdate entries in the routing table for any stale MPP(s). The entries inthe routing table may be updated in any suitable way. While theembodiment illustrated by FIG. 4 describes removing stale MPPs from therouting table, other embodiments of the invention may update the routingtable in other ways. For example, the routing table in some embodimentsof the invention may be ordered by priority. In such embodiments, therouting table may be updated to reflect stale MPP(s) by lowering thepriority of the stale MPP(s), such as by adjusting a priority score inthe routing table that may be associated with each MPP.

It is to be appreciated that the functionality ascribed to blocks 408and 410 does not have to be performed in response to receiving anadvertisement from an MPP. For example, In some embodiments of theinvention, the functionality ascribed to blocks 408 and 410 may beexecuted periodically by the mesh node in order to periodically clean upstale entries in the MPP routing table for the mesh node. In addition,in sonic embodiments of the invention, an MPP may be removed, such as inblock 410, from the routing table for other additional or alternativereasons. For example, if a mesh node determines that a networkconnection to a device outside the mesh network passing through aparticular MPP has failed, it may remove that MPP from the routingtable, and if appropriate, select a new default MPP.

Regardless of whether any stale MPP(s) were removed from the routingtable in block 410, the process proceeds to block 412, in which the MPPmay compute a metric for a path between itself and the MPP for which itjust received an advertisement, and store the metric in the routingtable. The metric may be determined in any suitable way, including beingderived based on information obtained from the gateway advertisementand/or calculated based on any suitable characteristics, as discussed inconjunction with FIG. 3A.

The process may then proceed to block 414. In some embodiments of theinvention, mesh nodes may forward any received advertisementsoriginating from a gateway to other mesh nodes. In doing so, a mesh nodemay include additional characteristics associated with the path betweenitself and the MPP. Any suitable additional characteristics may beincluded in the forwarded advertisement, as discussed in conjunctionwith FIG. 3A, including a number of hops in a network path between themesh node and the MPP.

At block 416, the process may then select a default MPP. This may bedone in any suitable way, including based on information stored in therouting table, such as the computed metrics associated with the path toeach MPP.

Once a default MPP is selected, in block 418, the process may thendirect network packets to the default MPP when communicating with acomputing device on an external network.

Besides gateway nodes, which provide a service of enabling connectivityto an external network, other mesh nodes may also provide services, suchas print and data services, that they advertise throughout the meshnetwork. In addition, it may also be useful for computing devices not onthe mesh network but within range of the mesh network to ascertain,without having to connect to the mesh network, whether a service isavailable over the mesh. However, the protocols used to distribute theadvertisements throughout the mesh typically cannot be used for devicesnot on the mesh network. FIG. 5 and associated FIGS. 5A and 5Billustrate a method of distributing service advertisements throughoutthe mesh network, as well as to computing devices outside the meshnetwork. FIGS. 5, 5A, and 5B may be implemented in any suitablecombination of hardware or software developed in any suitableprogramming language.

The method of FIG. 5 may be implemented on any suitable mesh node. Insome embodiments of the invention, only a subset of the mesh nodes in amesh network may perform all the steps of the method illustrated by FIG.5, while in other embodiments, the steps may be performed by each nodein the mesh. The method may start at block 502, in which a mesh nodereceives at least one service advertisement from another node in themesh. The received advertisement(s) were sent according to a firstprotocol, which in some embodiments of the invention may be a layerthree network protocol, such as a Universal Plug and Play (UPnP™)Discovery Protocol or a Web Services Discovery (WSD) Protocol. In thecase of an MPP advertisement, the protocol may also be an ICMP protocolin embodiments of the invention in which the advertisement is sentaccording to a protocol at a networking layer three or above, theadvertisement may not have been received by any computing devicesoutside the mesh network.

At block 504, the mesh node may then broadcast the receivedadvertisement to other mesh nodes, according to the first protocol,which may be a layer three networking protocol. The method then proceedsto block 506, in which the mesh node aggregates any layer threeadvertisements it has received, and converts them to a second protocol.The second protocol may be a protocol, such as layer two networkingprotocol, with which the mesh node is able to communicate with computingdevices outside the mesh network. In some embodiments of the invention,the second protocol may be a variant of a wireless Ethernet protocol,such as an 802.11s protocol.

The method proceeds then to block 508, in which the mesh node advertisesthe services provided in aggregate by the mesh network according to thesecond protocol, which may be a layer two protocol. The services may beadvertised according to the second protocol in any suitable way. FIGS.5A and 5B each illustrate a different method of implementing block 508.Some embodiments of the invention may include only one of the twomethods, while other embodiments may include both methods.

The method of FIG. 5A may be invoked on the mesh node by theimplementation of the method of FIG. 5. At block 522, the methodinvolves performing a layer two broadcast of the services provided inaggregate by the mesh network. Thus, any computing device not on themesh network, but that is within range of the mesh node and is capableof communicating over the same layer two protocol may receive theadvertisement broadcast by the mesh node. The layer two broadcast of theservices may be performed over any suitable protocol. It may be part ofa beacon or other wireless communication over a known protocol, such asa variant of wireless Ethernet (e.g., 802.11s). The layer two broadcastmay be according to a standard protocol, but may utilize optional fieldsin the standard protocol to indicate services advertised. In otherembodiments, the protocol may be a special purpose protocol that hasdefined fields for advertising in one message all the advertisingservices provided by the mesh, while in other embodiments according tosome protocols, the services may be advertised sequentially in separatemessages.

Regardless of the protocol used, besides broadcasting the availableservices, the broadcast performed at block 522 may also include abroadcast of the availability of the mesh network itself. Thus, a userof a computing device outside the mesh network may be made aware of thepresence of the mesh network, as well as the services provided by themesh network. The method of FIG. 5A is then complete, and process maythen continue with block 510 of the process of FIG. 5.

The method of FIG. 5B may also be invoked on the mesh node by theimplementation of the method of FIG. 5. At block 532, the method mayreceive a request for a particular service from a device outside themesh network. The request may be sent according to any suitable layertwo networking protocol, including a standard protocol, a variation of astandard, such as by the inclusion of optional fields, or a specialpurpose protocol, similar to the discussion in conjunction with FIG. 5A.For example, a user of a computing device that is interested inconnecting to a mesh network only if the mesh offers printingcapabilities, may configure his computing device to broadcast his intentusing layer two discovery messages, such as a printer search equivalent.Such a request may have been received by the mesh node in block 532.

At block 534, the mesh node may respond according to a layer twoprotocol to the request of the computing device outside the mesh, inwhich the response contains advertisements of services provided by themesh network. The response may be sent according to any suitablenetworking protocol. While in some embodiments of the invention, theresponse may be sent according to the same protocol used by the deviceoutside the mesh network to send the request, the response may also besent according to a different protocol than the request. The method ofFIG. 5B may then be complete, and the process may then continue withblock 510 of the process of FIG. 5.

Returning to FIG. 5, at block 510, the mesh node may then optionallyreceive a request to join the mesh network from a computing deviceoutside the mesh. A user of the computing device outside the mesh mayhave chosen to issue the request to join the mesh as a result of havingreceived an advertisement of the services provided by the mesh network.The process may then proceed to block 512, in which the mesh node mayoptionally negotiate with the device outside the mesh network to allowthe device to join the mesh network. The step of block 512 may beperformed in any suitable way, including known techniques for joining amesh network, as the invention is not limited in this respect. Theprocess illustrated by FIG. 5 may then have finished at this point.

While mesh nodes may provide numerous services, including gatewayservices, printing services, or data services, a mesh network maytypically not provide a DHCP service. However, it may still be desirablefor network addresses to be automatically assigned to nodes in a meshnetwork. Accordingly, FIG. 6 illustrates a method for a mesh node toautomatically assign a unique network address to itself, includingresolving any conflicts that may arise with other mesh nodes on the meshnetwork.

FIG. 6 may begin when a mesh node attempts to join the mesh network,whether that is for the first time, or after the mesh node has poweredon, for example. The method illustrated by FIG. 6 may be implemented inany suitable way, including by the address logic 227 in the embodimentof FIG. 2. In the embodiment illustrated by FIG. 6, once the mesh nodehas determined a network address that is unique throughout the mesh, itmay store that network address in a particular location in any suitablenon-volatile computer storage medium. Accordingly, at block 602, themesh node may check if a network address has been stored in theparticular location. If a network address has been stored, the processmay then proceed to block 608, in which the mesh node may optimisticallyassign the stored network address to itself under the assumption thatthe stored address is still unique throughout the mesh network. In block608, the device may also start sending or receiving network packets withother mesh nodes based on the assigned network address.

Otherwise, if it is determined at block 602 that no network address hasbeen stored in the particular location on the mesh node, the processproceeds to block 604, in which it may select a first portion of thenetwork address, such as an IF address prefix. The IP address prefix maycorrespond to an identifier for a subnet for the mesh network, andshared among other mesh nodes in the mesh network. In some embodimentsof the invention, the subnet may be preconfigured for a mesh node, andmay be in any suitable range of private network addresses. In someembodiments, the address may have a prefix such as, 169.254.x,x, whichis sometimes used for automatically assigned network addresses in othercontexts. However, in some embodiments, the assigned addresses have aprefix corresponding to a private address space, such as 10.x.x.x,172.16.x.x 192.168.x.x, allowing messages to be routed to nodes usingNAT operations. The length of the prefix is not a limiting factor of theinvention, and may be chosen based on a number of factors, including thenumber of expected nodes to which the mesh network is likely to grow.For example, if the prefix is of a length of 16 bits, in a 32-bitnetwork address, this allows 2¹⁶-1 mesh nodes to be uniquely addressedin the mesh network.

The process may then proceed to block 606, in which the process mayselect a second portion of the network address, such as an IP addresssuffix. In the embodiment of the invention illustrated by FIG. 6, thesecond portion of the network address is intended to be unique acrossother mesh nodes. The network address suffix may be computed in anysuitable way. In some embodiments of the invention, the suffix iscomputed by performing a hash operation on a unique identifier on themesh node, such as a MAC address of a network interface on the meshnode. Because the MAC address is unique throughout the mesh network, avalue computed based on the MAC address is also likely to be unique.However, other methods of selecting a unique suffix are possible,including manual assignment.

The process may then proceed to block 608 in which the mesh node mayassign to itself the network address obtained based on the selectedprefix and the computed suffix, and start sending or receiving networkpackets with other mesh nodes based on the assigned network address.

The process may then proceed to block 610, in which the mesh node mayattempt to detect if the assigned network address conflicts with anyother network addresses on the mesh. This may be done in any suitableway, including by using a duplicate address detection (DAD) protocol.DAD may be supported in the networking stack implementation of anoperating system loaded on the mesh node, such as the WINDOWS XP® andWINDOWS VISTA® operating systems developed by Microsoft Corporation. DADmay be implemented in any suitable way, including by using a gratuitousAddress Resolution Protocol (ARP). As is known in the art, ARP isusually employed for finding a computer's link layer address, such as aMAC address, when only its network layer address, such as an IP address,is known. A gratuitous ARP request is useful in that it is broadcast toall computers on a network. Thus, if a mesh node issues a gratuitous ARPrequest to all mesh nodes, in which the request contains the mesh node'snewly self-assigned IP address as the source address in the request, anymesh node that is assigned the same IP address may detect an addressconflict. In addition, nodes in the mesh may issue a reply to the ARPrequest. Based on the received replies, the mesh node can determine ifany of the mesh nodes replying are assigned the same address as theaddress it just assigned to itself.

Regardless of the method of detecting a duplicate address in the meshemployed in block 610, at block 612, the mesh node may determine whetheror not a conflict was detected in block 612, if a conflict was detectedwith another node on the mesh, the process proceeds to block 614, inwhich the mesh node may check to see whether it has exceeded a specifiedamount of time or a specified number of tries in determining a uniquenetwork address. The value for the specified amount of time or thespecified number of tries may be obtained in any suitable way, includingas a configurable setting on the mesh node. If the mesh node hasexceeded the specified amount of time or the specified number of tries,the method may then terminate with an error.

Otherwise, the process may proceed to block 616 in which a new networkaddress suffix may be selected. A new network address suffix may beselected in any suitable way, in some embodiments of the invention, thenew MAC address suffix may be generated by incrementing the value of theconflicting suffix. In other embodiments, the mesh node may obtain a newsuffix value, such as a random number, from a user of the mesh node.

In some embodiments of the invention, the steps performed by block 616are only performed by a subset of any conflicting nodes on the mesh. Forexample, if the mesh node detects that its network address conflictswith a second mesh node on the mesh network, only one of the two meshnodes may perform the steps in block 616. The determination regardingwhich subset of conflicting nodes may perform the steps of block 616 maybe made in any suitable way, including by basing the determination onthe value of each node's MAC address. For example, in some embodiments,only the mesh node with a MAC address having a higher numerical valuemay perform the steps in block 616 to obtain a new network address,while in other embodiments the mesh node having the lower valued MACaddress may be the only node to obtain a new network address. Otherembodiments may randomly select which subset of conflicting mesh nodesmay obtain a new network address, based on any suitable alternativecriteria.

Once a new network address suffix is determined in block 616, theprocess proceeds back to block 608 in which the process will attempt touse the new network address based on the new suffix, and then proceed toblock 610 in which the mesh node may detect if the new network addressresults in any conflicts. If the mesh node determines at block 612 thata new conflict has arisen, the process continues to block 614, asdiscussed above.

Otherwise, if it is determined at block 612 that the network addressdoes not conflict with any other network addresses on the mesh network,the process may then proceed to block 618, in which the mesh node maystore the network address in the particular location in the same datastorage medium discussed in conjunction with block 602. The methodillustrated by FIG. 6 may then be finished at this point.

It is to be appreciated that a subset of the functionality ascribed tothe method illustrated by FIG. 6 may be performed repeatedly by the meshnode, even if it is already using a network address and does not have aneed to assign a network address to itself. For example, the method maycontinually check at block 610 whether the network address it is usingconflicts with any other address on the mesh network.

Having thus described several aspects of at least one embodiment of thisinvention, it is to be appreciated that various alterations,modifications, and improvements will readily occur to those skilled inthe art.

Such alterations, modifications, and improvements are intended to bepart of this disclosure, and are intended to be within the spirit andscope of the invention. Accordingly, the foregoing description anddrawings are by way of example only.

For example, a gateway node may act as a discovery proxy, such as a DNSproxy or as a WSD discovery proxy, broadcast and/or multicast protocols.In such examples, the gateway node may capture services that areprovided outside the mesh network, and may reply to service requestswithin the mesh. One use of a gateway node acting as a proxy may be toallow address resolution (i.e., discovery) for computers providingservices outside the mesh, such as computers providing Network BasicInput/Output System (NetBIOS) services, and to reply to other mesh nodeson behalf of the computer outside the mesh. Such address resolution maybe implemented on a gateway node acting as a proxy in any suitable way,including manual configuration, or automatically discovering servicesoutside the mesh network for which the gateway node may act as a proxy.A method similar to that used to select a default gateway node may alsobe used to select a gateway node that acts as a proxy for a particularservice. In some embodiments, the default gateway node selected for amesh node may be different than the selection of a default gatewayacting as a proxy for a particular service, as the invention is notlimited in this respect.

Additionally, in some embodiments, the same protocol used for theadvertising of a gateway node throughout the mesh network may also beused by other mesh nodes advertising other types of services, in otherembodiments, even if nodes advertising other types of services do notuse the same advertisement protocol as a gateway node, aspects of thegateway advertisement protocol or the format of the advertisementsdiscussed in conjunction with gateway nodes may also apply to otherservice advertisements. For example, each mesh node receiving a serviceadvertisement may obtain characteristics contained within theadvertisement to compute a metric associated with a path between itselfand the node providing a service, and may use that path to select a nodefrom which it will receive a service. For example, if multiple meshnodes advertise printing services, a mesh node receiving theadvertisements may select a default printing service node, based oncharacteristics associated with a path from the mesh node to each nodeproviding printing services.

As another example, the service provider nodes may distributeadvertisements at periodic intervals, and may include the interval inthe service advertisement. Based on whether or not it has received anadvertisement in an expected time interval from a node providing aservice, a mesh node may be able to track mesh nodes that currentlyprovide services in the mesh network in a dynamic way that takes intoaccount changed conditions in the mesh, such as the departure or arrivalof a mesh node.

The above-described embodiments of the present invention can beimplemented in any of numerous ways. For example, the embodiments may beimplemented using hardware, software or a combination thereof. Whenimplemented in software, the software code can be executed on anysuitable processor or collection of processors, whether provided in asingle computer or distributed among multiple computers.

Further, it should be appreciated that a computer may be embodied in anyof a number of forms, such as a rack-mounted computer, a desktopcomputer, a laptop computer, or a tablet computer. Additionally, acomputer may be embedded in a device not generally regarded as acomputer but with suitable processing capabilities, including a PersonalDigital Assistant (PDA), a smart phone or any other suitable portable orfixed electronic device.

Also, a computer may have one or more input and output devices. Thesedevices can be used, among other things, to present a user interface.Examples of output devices that can be used to provide a user interfaceinclude printers or display screens for visual presentation of outputand speakers or other sound generating devices for audible presentationof output. Examples of input devices that can be used for a userinterface include keyboards, and pointing devices, such as mice, touchpads, and digitizing tablets. As another example, a computer may receiveinput information through speech recognition or in other audible format.

Such computers may be interconnected by one or more networks in anysuitable form, including as a local area network or a wide area network,such as an enterprise network or the Internet. Such networks may bebased on any suitable technology and may operate according to anysuitable protocol and may include wireless networks, wired networks orfiber optic networks.

Also, the various methods or processes outlined herein may be coded assoftware that is executable on one or more processors that employ anyone of a variety of operating systems or platforms. Additionally, suchsoftware may be written using any of a number of suitable programminglanguages and/or programming or scripting tools, and also may becompiled as executable machine language code or intermediate code thatis executed on a framework or virtual machine.

In this respect, the invention may be embodied as a computer readablemedium (or multiple computer readable media) (e.g., a computer memory,one or more floppy discs, compact discs, optical discs, magnetic tapes,flash memories, circuit configurations in Field Programmable Gate Arraysor other semiconductor devices, or other tangible computer storagemedium) encoded with one or more programs that, when executed on one ormore computers or other processors, perform methods that implement thevarious embodiments of the invention discussed above. The computerreadable medium or media can be transportable, such that the program orprograms stored thereon can be loaded onto one or more differentcomputers or other processors to implement various aspects of thepresent invention as discussed above.

The terms “program” or “software” are used herein in a generic sense torefer to any type of computer code or set of computer-executableinstructions that can be employed to program a computer or otherprocessor to implement various aspects of the present invention asdiscussed above. Additionally, it should be appreciated that accordingto one aspect of this embodiment, one or more computer programs thatwhen executed perform methods of the present invention need not resideon a single computer or processor, but may be distributed in a modularfashion amongst a number of different computers or processors toimplement various aspects of the present invention.

Computer-executable instructions may be in many forms, such as programmodules, executed by one or more computers or other devices. Generally,program modules include routines, programs, objects, components, datastructures, etc. that perform particular tasks or implement particularabstract data types. Typically the functionality of the program modulesmay be combined or distributed as desired in various embodiments.

Also, data structures may be stored in computer-readable media in anysuitable form. For simplicity of illustration, data structures may beshown to have fields that are related through location in the datastructure. Such relationships may likewise be achieved by assigningstorage for the fields with locations in a computer-readable medium thatconveys relationship between the fields. However, any suitable mechanismmay be used to establish a relationship between information in fields ofa data structure, including through the use of pointers, tags or othermechanisms that establish relationship between data elements.

Various aspects of the present invention may be used alone, incombination, or in a variety of arrangements not specifically discussedin the embodiments described in the foregoing and is therefore notlimited in its application to the details and arrangement of componentsset forth in the foregoing description or illustrated in the drawings.For example, aspects described in one embodiment may be combined in anymanner with aspects described in other embodiments.

Also, the invention may be embodied as a method, of which an example hasbeen provided. The acts performed as part of the method may be orderedin any suitable way. Accordingly, embodiments may be constructed inwhich acts are performed in an order different than illustrated, whichmay include performing some acts simultaneously, even though shown assequential acts in illustrative embodiments.

Use of ordinal terms such as “first,” “second,” “third,” etc., in theclaims to modify a claim element does not by itself connote anypriority, precedence, or order of one claim element over another or thetemporal order in which acts of a method are performed, but are usedmerely as labels to distinguish one claim element having a certain namefrom another element having a same name (but for use of the ordinalterm) to distinguish the claim elements.

Also, the phraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting. The use of“including,” “comprising,” or “having,” “containing,” “involving,” andvariations thereof herein, is meant to encompass the items listedthereafter and equivalents thereof as well as additional items.

1. A method performed on a computing device coupled to a mesh network,the method comprising: receiving, by the computing device via a layerthree or above networking protocol, a service advertisement from withinthe mesh network; converting, by the computing device, the receivedservice advertisement from the layer three networking protocol to alayer two networking protocol; and advertising, by the computing devicevia the layer two networking protocol, the received serviceadvertisement on the mesh network.
 2. The method of claim 1 where theadvertising comprises broadcasting, on the mesh network via the layertwo networking protocol, the received service advertisement.
 3. Themethod of claim 1 where the advertising comprises: receiving, via asecond layer two networking protocol from a device outside the meshnetwork, a request for a service corresponding to the received serviceadvertisement; and responding, to the requesting device via the secondlayer two networking protocol, the received service advertisement. 4.The method of claim 1 where the layer three or above networking protocolcomprises a Universal Plug and Play (“UPnP”) Discovery Protocol or a WebServices Discovery (“WSD”) Protocol or Internet Control Message Protocol(“ICMP”).
 5. The method of claim 1 where the layer two networkingprotocol comprises a variant of a wireless Ethernet protocol.
 6. Themethod of claim where the service advertisement as advertised isaggregated with other service advertisements for other services providedby the mesh network.
 7. The method of claim 6 where the aggregatedservice advertisements are advertised in a single message, where thesingle message is in the form of a beacon or a wireless communication orsome other format.
 8. A computing device configured to be coupled to amesh network, the computing device comprising: at least one processor;memory; and at least one program module via which the computing deviceis configured to: receive, via a layer three or above networkingprotocol, a service advertisement from within the mesh network; convertthe received service advertisement from the layer three networkingprotocol to a layer two networking protocol; and advertise, via thelayer two networking protocol, the received service advertisement on themesh network.
 9. The computing device of claim 8 where the serviceadvertisement is advertised by broadcasting the service advertisement onthe mesh network via the layer two networking protocol.
 10. Thecomputing device of claim 8 where the service advertisement isadvertised: in response to receiving, via a second layer two networkingprotocol from a device outside the mesh network, a request for a servicecorresponding to the received service advertisement; and by responding,to the requesting device via the second layer two networking protocol,the received service advertisement.
 11. The computing device of claim 8where the layer three or above networking protocol comprises a UniversalPlug and Play (“UPnP”) Discovery Protocol or a Web Services Discovery(“WSD”) Protocol or Internet Control Message Protocol (“ICMP”).
 12. Thecomputing device of claim 8 where the layer two networking protocolcomprises a variant of a wireless Ethernet protocol.
 13. The computingdevice of claim 8 where the service advertisement as advertised isaggregated with other service advertisements for other services providedby the mesh network.
 14. The computing device of claim 13 where theaggregated service advertisements are advertised in a single message,where the single message is in the form of a beacon or a wirelesscommunication or some other format.
 15. At least one computer-readablemedium comprising: at least one memory that includes at least oneprogram module comprising computer-executable instructions that, whenexecuted by a computing device configured to be coupled to a meshnetwork, cause the computing device to: receive, via a layer three orabove networking protocol, a service advertisement from within the meshnetwork; convert the received service advertisement from the layer threenetworking protocol to a layer two networking protocol; and advertise,via the layer two networking protocol, the received serviceadvertisement on the mesh network.
 16. The at least onecomputer-readable medium of claim 15 where the service advertisement isadvertised by broadcasting the service advertisement on the mesh networkvia the layer two networking protocol.
 17. The at least onecomputer-readable medium of claim 15 where the service advertisement isadvertised: in response to receiving, via a second layer two networkingprotocol from a device outside the mesh network, a request for a servicecorresponding to the received service advertisement; and by responding,to the requesting device via the second layer two networking protocol,the received service advertisement.
 18. The at least onecomputer-readable medium of claim 15 where the layer three or abovenetworking protocol comprises a Universal Plug and Play (“UPnP”)Discovery Protocol or a Web Services Discovery (“WSD”) Protocol orInternet Control Message Protocol (“ICMP”), or where the layer twonetworking protocol comprises a variant of a wireless Ethernet protocol.19. The at least one computer-readable medium of claim 15 where theservice advertisement as advertised is aggregated with other serviceadvertisements for other services provided by the mesh network.
 20. Theat least one computer-readable medium of claim 19 where the aggregatedservice advertisements are advertised in a single message, where thesingle message is in the form of a beacon or a wireless communication orsome other format.